The subject matter described and/or illustrated herein relates generally to card edge connectors.
Computers and servers use numerous types of electronic modules, such as processor and memory modules (e.g. Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), or Extended Data Out Random Access Memory (EDO RAM), and the like). The memory modules are produced in a number of formats such as, for example, Single In-line Memory Modules (SIMM's), Dual In-line Memory Modules (DIMM's), Small Outline DIMM's (SODIMM's), Fully Buffered DIMM's, and the like. The electronic modules may be installed in card edge connectors that are mounted on a motherboard or other system board.
Electronic modules often include a printed circuit board (PCB) having a card edge that is received within a card slot of the card edge connector. The PCB includes contact pads arranged along the card edge on two opposite sides of the PCB. The card edge connector includes a pair of opposite rows of electrical contacts extending within the card slot. When the card edge of the PCB is received within the card slot, the electrical contacts of each row of the card edge connector engage the contact pads on a corresponding one of the sides of the PCB. The electrical contacts and the contact pads are typically arranged in differential signal pairs. Ground contacts and ground contact pads are sometimes positioned between adjacent differential pairs within the rows of electrical contacts and contact pads, respectively. The ground contacts and contact pads facilitate decreasing crosstalk between adjacent differential signal pairs. But, the proximity of the ground contacts and ground contact pads to the differential pairs may reduce the impedance of signals transmitted through the differential pairs, which may reduce the efficiency of data transfer through the card edge connector.